Tocolysis and preterm labour

Inhibitory effect and underlying mechanism of essential oil of Prangos ferulacea Lindl (L.) on spontaneous and induced uterine contractions in non-pregnant rats

Evidence suggests the use of natural compounds as support in the management of uterine contractility disorders. We recently demonstrated that the essential oil of Apiacea Prangos ferulacea (L.) (Prangoil) modulates intestinal smooth muscle contractility. Thus, we aimed to evaluate if Prangoil could also affect the contractility of uterine muscle in non-pregnant rat and to investigate the related action mechanism/s. The effects of the aromatic monoterpenes, β-ocimene and carvacrol, constituents of Prangoil, were also evaluated. Spontaneous contractions and contraction-induced by K+-depolarization and oxytocin in rat uterus were recorded in vitro, using organ bath technique. Prangoil reduced the amplitude of spontaneous contractions as well as responses to KCl and oxytocin. β-ocimene and carvacrol matched oil inhibitory effects. Prangoil effects were not affected by nitrergic and adenylyl cyclase inhibitors or non-specific potassium channel blocker, but they were reduced by nifedipine, L-type calcium channel inhibitor, or 2-aminoethoxydiphenylborate (2-APB), membrane-permeant inositol 1,4,5-triphosphate receptor inhibitor. The response to β-ocimene was reduced by nifedipine and by 2-APB (20 μM), whilst carvacrol inhibitory effect was attenuated only by nifedipine. In conclusion, Prangoil, and its components, β-ocimene and carvacrol, reduced spontaneous and KCl or oxytocin-induced contractions of rat myometrium, mainly modulating extracellular Ca2+ influx through L-Type channels and Ca2+ release from the intracellular store. Further studies could contribute to evaluate the potential use of Prangoil against disorders characterized by abnormal uterine contractions.

Measurement of the uterocervical angle for the prediction of preterm birth in symptomatic women

Purpose

To examine if the uterocervical angle (UCA) can be used to predict preterm delivery in women with painful and regular uterine contractions and a cervical length of 25 mm or less.

Methods

Retrospective study at the perinatal unit of the University Hospital of Tuebingen, Germany. Women with singleton gestation and preterm contractions between 24 + 0 and 33 + 6 weeks’ gestation were included. For the UCA measurement, a line is placed from the internal os to the external os irrespective of whether the cervix is straight or curved. A second line is drawn to delineate the lower uterine segment. The angle between the two lines is the UCA measurement. The measurements were taken on stored images from our database.

Results

The study consisted of 213 singleton pregnancies. At the time of UCA measurement, median maternal and gestational age was 31.4 years and 29.7 weeks’ gestation. Median gestational age at delivery was 35.3 weeks and the corresponding birth weight 2480 g, respectively. The UCA measurement in women who delivered within 2 days, between 3–7 days and after 7 days was not helpful to distinguish between these three groups [median UCA measurements: 108.5°, 108.0° and 107.3° (Kruskal–Wallis test p = 0.576)]. Uni- and multivariate logistic multiple regression analysis demonstrated that the delivery within 2 days was only dependent on the gestational age and the cervical length at the time of presentation.

Conclusion

The measurement of UCA is not useful in predicting preterm birth in the subsequent 7 days after an episode of preterm contractions.

Association of Maternal History of Allergic Features with Preterm Pregnancy Outcomes in the Japan Environment and Children's Study

INTRODUCTION

Previous studies have reported that maternal asthma increases the risk of preterm birth. We hypothesized that inflammatory reactions caused by allergic diseases might affect the uterine environment and, subsequently, perinatal outcomes. The objective of this study was to examine the associations between allergic features among mothers and preterm pregnancy outcomes in a nationwide birth cohort.

METHODS

We analyzed data from pregnant women obtained from the Japanese Environment and Children's Study (JECS), a nationwide general birth cohort study. We used binomial and multinomial logistic regression models to examine the associations between maternal allergic features and preterm birth, threatened preterm labor (TPL), and preterm premature rupture of the membrane (PPROM).

RESULTS

A total of 97,683 pregnant women were included. Prevalence of preterm birth, TPL, and PPROM was 4.7, 19.6, and 1.2%, respectively. Maternal history of allergic diseases (asthma, allergic rhinitis, allergic conjunctivitis, food allergy, drug allergy, and contact dermatitis) increased the risk of TPL(adjusted odds ratio [aOR] = 1.11 [95% CI: 1.06-1.17], aOR = 1.12 [1.08-1.16], aOR = 1.10 [1.04-1.16], aOR = 1.17 [1.09-1.26], aOR = 1.35 [1.23-1.48], and aOR = 1.34 [1.20-1.49], respectively). Although some maternal allergic features showed a negative association with preterm birth, the variables affecting preterm birth differed according to the gestational age of the fetus (22-33 weeks vs. 34-36 weeks). There were no significant associations between maternal allergic features and PPROM.

CONCLUSION

Maternal allergic disease, except atopic dermatitis, may increase the risk of TPL. Comorbidity of maternal allergic disorders and perinatal adverse outcomes require further investigation.

Tocolytic effect of the monoterpenic phenol isomer, carvacrol, on the pregnant rat uterus

Despite the wide application of carvacrol (CAR) in different biological and medical areas, there is still insufficient electrophysiological data on the mechanisms of action of CAR, particularly in the pregnant uterine function. The aim of this study was to evaluate the in vitro tocolytic effect of CAR on the contractility of isolated pregnant rat uterus in the presence of a calcium channel antagonist (nifedipine) and a cyclooxygenase inhibitor (indomethacin). The uteri were isolated from pregnant Wistar rats at 16-18 days of pregnancy and suspended in an isolated organ bath chamber containing a Ringer's physiological solution and aerated with 95% O₂and 5% CO₂. Samples were used in functional tests to evaluate the inhibitory effect of CAR at increasing concentrations on the rhythmic spontaneous, oxytocin-induced phasic, K⁺-induced tonic, and Ca²⁺-induced contractions. The differences in inhibitory concentration-50 and E_maxamong the compounds were determined using the one-way ANOVA followed by a post hoc Student-Newman-Keuls or Bonferroni test, in all casesP < 0.05 was considered statistically significant. Nifedipine was used as positive controls where required. CAR caused a significant concentration-dependent inhibition of the uterine contractions induced by the pharmaco- and electro-mechanic stimuli. We showed that the inhibitory effects of CAR depends on the type of muscle contraction stimuli, and that it acts stronger in spontaneous rhythmic activity and in contractions of isolated rat uterus induced by Ca²⁺. Nifedipine was more potent than CAR and indomethacin on the uterine contractility (P < 0.05), but none of them was more effective than nifedipine. Therefore, the tocolytic effect induced by CAR was associated with the blockade of the calcium channels in the pregnant rat uterus. This property placed CAR as a potentially safe and effective adjuvant agent in cases of preterm labor, an area of pharmacological treatment that requires urgent improvement.

Antenatal corticosteroids for women at risk of preterm delivery: the "Emperor's New Clothes" tale in medical practice

Objective: To introduce the effect of a single course of betamethasone for pregnant women at risk of preterm delivery (PTD).Materials and methods: In this study, a single course of 12 mg Bethamethasone was administered twice in 24 h (between 24-34 gestational weeks) for antenatal corticosteroid prophylaxis. Four hundred ninety-three neonates fulfilled the inclusion criteria and they were categorized (259 singletons, 192 twins and 42 triplets who met the inclusion criteria) into two groups according to the utilization of antenatal corticosteroid as control (n = 202) and study (n = 291) groups. We used respiratory distress syndrome (RDS), congenital pneumonia, intraventricular hemorrhage (IVH), neonatal sepsis, and bronchopulmonary dysplasia (BPD) as primary outcomes for the evaluation of neonatal morbidity.Results: Study and control groups were similar in terms of clinical characteristics. RDS, congenital pneumonia, neonatal sepsis, and BPD rates were significantly higher in the study group (betamethasone) (p = .05, p = .007, 0.003, and 0.004, respectively) between 24-34 gestational weeks (when the neonates of multiple pregnancies were excluded from the analysis, we have demonstrated that congenital pneumonia (p = .033) and neonatal sepsis (p = .030) were still significantly higher in the betamethasone group). The neonates of 24-28 gestational weeks were compared separately and we demonstrated that RDS (p = .012), congenital pneumonia (p = .022), IVH (p = .044), neonatal sepsis (p = .023), and BPD (0.001) were also more frequent in the study group. When the 28-32 gestational week data were compared, IVH (p = .020) and neonatal sepsis (p = .017) were more frequent in the single course betamethasone users. However, we could not demonstrate a significant difference between the control and study groups between 32-34 gestational weeks in terms of the primary neonatal outcomes used in this study.Conclusion: Single course antenatal betamethasone administration may be ineffective on the respiratory complications of preterm and very preterm infants while it may be unfavorable for extremely preterm infants.What is new about the paper, what could add to the current knowledge: Pregnant women at risk for preterm labor must be under intensive antenatal care programs, and if possible, necessary precautions must be undertaken to prevent fetal hypoxia together with etiology specific treatments. This approach might contribute to better perinatal outcomes than just administering antenatal corticosteroid therapy.

Study protocol for a randomised trial for atosiban versus placebo in threatened preterm birth: the APOSTEL 8 study

INTRODUCTION

Preterm birth complicates >15 million pregnancies annually worldwide. In many countries, women who present with signs of preterm labour are treated with tocolytics for 48 hours. Although this delays birth, it has never been shown to improve neonatal outcome. In 2015, the WHO stated that the use of tocolytics should be reconsidered and that large placebo-controlled studies to evaluate the effectiveness of tocolytics are urgently needed.

METHODS AND ANALYSIS

We designed an international, multicentre, randomised, double-blinded, placebo-controlled clinical trial. Women with threatened preterm birth (gestational age 30-34 weeks), defined as uterine contractions with (1) a cervical length of < 15 mm or (2) a cervical length of 15-30 mm and a positive fibronectin test or (3) in centres where cervical length measurement is not part of the local protocol: a positive fibronectin test or insulin-like growth factor binding protein-1 (Actim-Partus test) or (4) ruptured membranes, will be randomly allocated to treatment with atosiban or placebo for 48 hours. The primary outcome is a composite of perinatal mortality and severe neonatal morbidity. Analysis will be by intention to treat. A sample size of 1514 participants (757 per group) will detect a reduction in adverse neonatal outcome from 10% to 6% (alpha 0.05, beta 0.2). A cost-effectiveness analysis will be performed from a societal perspective.

ETHICS AND DISSEMINATION

This study has been approved by the Research Ethics Committee (REC) of the Amsterdam University Medical Centres, location AMC, as well as the REC's in Dublin and the UK. The results will be presented at conferences and published in a peer-reviewed journal. Participants will be informed about the results.

TRIAL REGISTRATION NUMBER

Nederlands Trial Register (Trial NL6469).

Cytokine profiles of umbilical cord blood mononuclear cells upon in vitro stimulation with lipopolysaccharides of different vaginal gram-negative bacteria

Inflammatory immune responses induced by lipopolysaccharides (LPS) of gram-negative bacteria play an important role in the pathogenesis of preterm labor and delivery, and in neonatal disorders. To better characterize LPS-induced inflammatory response, we determined the cytokine profile of umbilical cord blood mononuclear cells (UBMC) stimulated with LPS of seven vaginal gram-negative bacteria commonly found in pregnant women with preterm labor and preterm rupture of membrane. UBMC from ten newborns of healthy volunteer mothers were stimulated with purified LPS of Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Proteus mirabilis, Acinetobacter calcoaceticus, Citrobacter freundii, and Pseudomonas aeruginosa. UBMC supernatants were tested for the presence of secreted pro-inflammatory cytokines (IL-6, IL-1β, TNF), anti-inflammatory cytokine (IL-10), TH₁-type cytokines (IL-12, IFN-γ), and chemokines (IL-8, MIP-1α, MIP-1β, MCP-1) by Luminex technology. The ten cytokines were differentially induced by the LPS variants. LPS of E. coli and E. aerogenes showed the strongest stimulatory activity and P. aeruginosa the lowest. Interestingly, the ability of UBMC to respond to LPS varied greatly among donors, suggesting a strong individual heterogeneity in LPS-triggered inflammatory response.

Inappropriate use of ritodrine hydrochloride for threatened preterm birth in Japan: a retrospective cohort study using a national inpatient database

Background

No study has revealed the effectiveness of long-term tocolysis for patients diagnosed with threatened preterm birth, and the use of betamimetics in these patients has not been recommended in the United States or Europe because of the potential for severe maternal adverse effects. However, long-term tocolysis with intravenous infusion of ritodrine hydrochloride, a betamimetic, can be selected as the first-line tocolytic treatment in Japan. This study was performed to (i) examine the current status of long-term tocolytic treatment, particularly with intravenous infusion of betamimetics, for threatened preterm birth in Japan and (ii) clarify the association between long-term tocolytic treatment and maternal adverse effects.

Methods

This retrospective cohort study was conducted using a national inpatient database for acute-care inpatients in Japan. Among all pregnant women who were diagnosed with threatened preterm birth and admitted to the hospital from July 2010 to March 2016, we identified 134,959 eligible patients. The primary outcome was maternal serious adverse effects during hospitalization. A multivariable logistic regression analysis was performed to evaluate factors associated with maternal adverse effects.

Results

Among all patients, 17.2% received intravenous infusion of ritodrine hydrochloride for ≤48 h and 28.7% received this treatment for ≥28 days. The proportion of maternal adverse effects was significantly higher among patients treated for ≥28 days than ≤48 h. A longer duration of tocolysis was significantly associated with increased maternal adverse effects.

Conclusions

Long-term tocolysis was associated with an increased incidence of maternal adverse effects in the current study using real-world data. Japanese clinicians should adjust their tocolytic treatment practices in accordance with the latest scientific evidence or make efforts to verify the effectiveness and safety of long-term tocolysis.

Association between rehabilitation during hospitalization and perinatal outcomes among pregnant women with threatened preterm birth

OBJECTIVE

This study conducted a nationwide retrospective cohort study to evaluate whether rehabilitation for pregnant women during long-term hospitalization is associated with adverse perinatal events.

METHODS

We performed a retrospective cohort study using a diagnosis procedure combination (DPC) database, a national inpatient database for acute-care inpatients in Japan. Hospitalized pregnant women diagnosed with threatened preterm birth, who stayed in the hospital for 7 days or longer from July 2010 to March 2017 in Japan were identified. One-to-four propensity score-matched analyses were performed to compare perinatal outcomes between patients with and without rehabilitation during hospitalization. The primary outcome was preterm birth (<35/0 weeks of gestation) during hospitalization.

RESULTS

Of the 141,705 eligible patients, 351 (0.25%) received any type of rehabilitation during hospitalization. One-to-four propensity score matching created a rehabilitation group (n = 338) and a nonrehabilitation group (n = 1352). The propensity-matched analysis showed that the proportion of preterm births in the rehabilitation group was lower than that in the nonrehabilitation group (5.9% versus 8.9%; risk difference: -3.0%; 95% confidence interval (CI): -5.9 to -0.03).

CONCLUSIONS

This retrospective nationwide study suggests that rehabilitation for hospitalized patients with threatened preterm birth may reduce the risk of preterm birth.

BRIEF RATIONALE

In this nationwide study, we suggest that rehabilitation for long-term hospitalized patients with threatened preterm birth may reduce the risk of preterm birth.

Antenatal corticosteroid administration in women undergoing tocolytic treatment who delivered before 34 weeks of gestation: a retrospective cohort study using a national inpatient database

Background

Antenatal corticosteroid treatment is globally recommended for women at risk of giving birth before 34 weeks of gestation. In Japan, data on the rate of completing recommended antenatal corticosteroid treatment are lacking. This study aimed to: (i) determine the proportion of patients treated for threatened preterm birth with tocolysis who received antenatal glucocorticoids; and (ii) analyze the association between long-term tocolysis and antenatal glucocorticoids treatment as recommended.

Methods

This was a retrospective cohort study using a national inpatient database in Japan. We selected pregnant women who had undergone treatment in hospitals due to threatened preterm birth and received the tocolytic ritodrine hydrochloride by infusion from July 2010 to March 2016, and delivered at < 34 weeks of gestation. The primary outcome was receiving of antenatal glucocorticoid treatment as recommended. Multivariable logistic regression was performed to evaluate factors associated with receiving antenatal glucocorticoid treatment.

Results

Only 23% of 4048 eligible patients received glucocorticoid treatment as recommended. Those with longer durations of ritodrine hydrochloride infusion were significantly less likely to receive glucocorticoid treatment as recommended.

Conclusions

In Japan, many patients who receive tocolytic treatment for threatened preterm birth do not receive antenatal glucocorticoid treatment as recommended. Recommended treatment based on apparent evidences should be performed for the patients with threatened preterm birth.

Differences between evidence-based recommendations and actual clinical practice regarding tocolysis: a prospective multicenter registry study

BACKGROUND

International guidelines recommend that tocolytic therapy be restricted to a single 48-h application. However, multiple cycles of tocolytic therapy and maintenance therapy that exceeds 48 h appear to play a role in daily clinical practice. We aimed to evaluate current trends in clinical practice with respect to treatment with tocolytic agents and to identify differences between evidence-based recommendations and daily clinical practice in Austria.

METHODS

A prospective multicenter registry study was conducted from October 2013 through April 2015 in ten obstetrical departments in Austria. Women ≥18 years of age who received tocolytic therapy following a diagnosis of threatened preterm birth were included, and details were obtained regarding clinical characteristics, tocolytic therapy, and pregnancy outcome.

RESULTS

A total of 309 women were included. We observed a median of 2 cycles of tocolytic therapy per patient (IQR 1-3) with a median duration of 2 days per cycle (IQR 2-5). Repeat tocolysis was administered in 41.7% of women, resulting in up to six tocolysis cycles; moreover, 40.8% of the first tocolysis cycles were maintenance tocolysis (i.e., longer than 48 h). Only 25.6% of women received one single 48-h tocolysis cycle in which they received antenatal corticosteroids for fetal lung maturation in accordance evidence-based recommendations.

CONCLUSIONS

Here, we report a clear disparity between evidence-based recommendations and daily practice with respect to tocolysis. We believe that the general practice of prescribing tocolytic therapy must be revisited. Furthermore, our findings highlight the need for contemporary studies designed to investigate the effectiveness of performing maintenance and/or repetitive tocolysis treatment.

Prevention of lipopolysaccharide-induced preterm labor by the lack of CX3CL1-CX3CR1 interaction in mice

Preterm labor (PTL) is the most common cause of neonatal death and long-term adverse outcome. The pharmacological agents for PTL prevention are palliative and frequently fail to prevent PTL and improve neonatal outcome. It is essential to fully understand the molecular mechanisms of PTL in order to develop novel therapeutic methods against PTL. Several lines of evidence indicate some chemokines are expressed in gestational tissues during labor or PTL. To reveal the pathophysiological roles of the CX3CL1-CX3CR1 axis in PTL, we performed present study using LPS-induced PTL mice model in CX3CR1-deficient (Cx3cr1^-/-) mice. We indicated that PTL was suppressed in Cx3cr1^-/- mice and immunoneutralization of CX3CL1 in WT mice. From immunohistochemical and the gene expression analyses, the CX3CL1-CX3CR1 axis has detrimental roles in PTL through intrauterine recruitment of macrophages and the enhancement of macrophage-derived inflammatory mediators. Thus, the CX3CL1-CX3CR1 axis may be a good molecular target for preventing PTL.

Ethical challenges posed by clinical trials in preterm labor: a case study

This paper explores the ethical implications of a randomized double-blind clinical trial aimed to determine effectiveness and safety of an oxytocin receptor antagonist versus a betamimetic in the treatment of preterm labor, presented to a teaching hospital affiliated with a private university in Santiago, Chile. Though this trial protocol fulfills one of the conditions under which pregnant women could be enrolled in a clinical trial-the intervention has the potential to benefit the pregnant woman (by reducing adverse effects associated to salbutamol administration) and her fetus (if the new drug prolongs pregnancy)-there are some specific ethical issues raised. First, when to obtain consent is an important issue for clinical trials involving acute and unforeseen conditions that affect pregnant woman, e.g. preterm labor. Second, research must address the risk/benefit ratio for these two interdependent individuals, providing a good prospect of low risk and adequate benefit for both of them. Thirdly, specifically when a study is sponsored by a high-income country and conducted in a low- or middle-income country, decisions regarding ancillary care provisions for research participants should be made in advance. Lastly, researchers must consider the requirements for paternal consent based on cultural contexts.

Effectiveness of the contemporary treatment of preterm labor: a comparison with a historical cohort

OBJECTIVE

To compare the effectiveness of contemporary treatment of preterm labor to a historical cohort.

STUDY DESIGN

Retrospective matched case-control study to compare the outcomes of patients that were treated for preterm labor at the University Hospital of Tuebingen, Germany in 2014/2015 (current treatment cohort) and 2006/2007 (historical cohort). The study included women with singleton gestations who were admitted with the diagnosis of preterm labor between 24 + 0 and 34 + 0 weeks' gestation and a cervical length of ≤15 mm. Women in the historical cohort were hospitalized until either 34 weeks' gestation or until complete cessation of uterine contractions. They were treated with intravenous beta-mimetics continuously, received antibiotics based on the vaginal culture and corticosteroids regardless of cervical length measurement. Bed rest was always recommended. The current treatment cohort was tocolyzed with an oral calcium channel blocker for approximately 3 days followed by vaginal progesterone until 34 weeks' gestation. Corticosteroids were given only if the cervical length is ≤15 mm. Bed rest was not recommended.

RESULTS

The study population consisted of 110 pregnancies, 55 in the historical cohort and 55 in the current treatment cohort. At the time of admission, mean gestational age in both groups was 29.3 and 29.7 weeks. In the historical and current treatment cohort the length of the hospitalization was 24.0 and 5.5 days and tocolysis was given for 19.5 and 3.4 days, respectively. In the historical cohort, mean gestational age at delivery was 35.6 weeks. In 63.6% cases delivery occurred prior to 37 weeks. In the current treatment group mean gestational age at the delivery was 37.0 weeks and 36.4% were delivered prior to 37 weeks.

CONCLUSION

Short-term hospitalization and tocolysis followed by vaginal progesterone for maintenance tocolysis is more effective than a protocol which includes long-term hospital stay, beta-mimetics, antibiotics, and bed rest.